Improvement in machines for forging the heads of bolts



l. GREENWOOD.

lmpro-v-emehtfiri Machne's for 'Forging the Hea-dsof Bolts.

Patented Feb- 20,1872.

f NM 5e" yq Jawa A- x a? '73.

. .4M Moro-umasmP//lc ca. M x (ossa/*Nn* maras!! Unrrnn STATES PATENT @rrron JEREMIAH GREENWOOD, OF FITOHBURG, MASSACHUSETTS.

IMPROVEMENT lN MACHINES FOR FQRGING THE HEADS QF BOLTS.

Specification forming part of Letters Patent No. 123,822, dated February 20, 1872.

To all whom yit may concern:

Be it known that I, J EREMIAH GREENWOOD, of Fitchburg, in the county of Vorcester and State of Massachusetts, have invented certain ncw and useful Improvements in Machines for Forging Heads upon Bolts; and I do hereby declare that the following, taken in connection with the drawing which accompanies and forms part of this specification, is a description of my invention sufticient to enable those skilled in the a-rt to practice it.

M y invention is designed to produce upon heated round iron heads of any polygonal forni, usually, however, hexagonal, and may be applied to any vertically-reciprocatin g hammer. ln my invention the heated iron is sustained in a rotating carrier, above which it projects sufficiently, so that the head can be formed by upsetting the material so projecting, the upsetting being performed by blows from a die carried by any suitable reciprocator, an dthe material so upsetbein g shaped to polygonal form by squeezers made to operate after each blow of the die, by the upward movement ot' the reciprocator, each upsetting blow preceding the action ot' the squeezers, which give, in connection with the degree of each partial rotation, the polygonal character of the head.

In the drawing, Figure l shows a vertical section of the parts involved in my invention and an elevation of what may be taken to represent a vertical hammer operated by steam or compressed air. Fig. 2 shows a side elevation ot' the saine; Fig. 3, a sectional plan, the section being taken in the plane ofthe dotted line seen in Fig. l; and Fig. 4 is a reversed sectional plan, showing the devices by which the carrier of the heated round iron is rotated.

a is supposed to represent the moving vertical cylinder of a Hotchkiss air-spring t'orgin ghammer in common use; b, the part of the piston-rod outside of the cylinder to which the hammer-die c is connected, the spring d representing the elastic cushion a'orded by air caught and confined between the piston and the cylinder-heads. In the lower part of the frame-work e of the forge-hammer is coniined, in place of the ordinary anvil, a casting, f, with which the parts embodying my invention are connected. Ooncentric with the axial line of the upsetting die c, and in the casting f, there is made a cylindrical recess, which receives carriers lf/made with central holes bored to suit any diameter' of round iron. These carriers are made to receive the ratchet-s h and i, by which the rotations of said carriers are effected and controlled, the lower end of each carrier fitting in a bearing in the ear j. In the bore of each carrier pins k, ofany length, may be inserted to determine the length of each bolt under the head. rlhe end of each gaugepin k rests on lever l, the end of the short arm of which rests on the casting e. By depressing the long arm of said lever the bolt occupying the bore of the carrier is raised out or thrown out therefrom. On opposite sides of the carrier are slides m m, made so that they can reciprocate in suitable ways fixed to the casting j', said slides serving as ways for the slides n n, which act as the dies by which the polygonal faces of the heads of the bolts are formed. To slides m m the levers o o are pivoted, the short arms thereof bearing against slides a n and the long arms being' brought into the path of the piece p attached to the reciprocating piece b. Said piece p, being angular at its top, opens or spreads levers o o as the piston and rod c b makes its upward stroke and causes the slides n a to move toward the center of carrier g, and to squeeze to shape any material that may be presented between the operative faces ot' said slides. Between cheeks q ot' casting f and slides m m are inserted inclines or wedges r r, the outer ends of slides m m having bevels or inclines corresponding to those of the wedges, which are caused to advance or to withdraw equally by the action on pins in the wedges of rocker-arms s s, which are slotted and which are fixed to rocker-shaft t, which is worked by hand by the lever u. The retractile movements of slides m a and the short arms of levers o o are eli'ected by the spring c, which acts directly on pins inserted in slides a a. The slide w is reciprocated by attachment to the moving cylinder a, and by means of an inclined slot in w effects reciprocations ot' a bar, which has pivoted to it a pawl, y, which works the ratchet z', a

detaining-pawl, z, operative on the same ratchet, preventing any reverse rotation while the pawl y iieets. To prevent motion in the direction. given by the pawl y during` the ac tion of the squeezing-dies h, t-he sliding-rod w is made to carry a pin, a', which is brought under a tooth ot' ratchet 7L before the dies n n operate, so that it will be seen that the carrier is held immovable during the movement of dies n a While operating to form two opposite sides of a polygonal head.

ln commencing to form a bolt-head, the wedges r r are pushed fully in, and as material is brought down by the action of the die o for dies a n to operate upon the wedges are drawn ont by the attendant, so that dies a a cease their inward strokes at points more and more remote from theY center of thebolt, the size or diameter ot' the bolt-head being determined by the distance to which the wedges r fr are drawn out\ Tard. The height or length of the bolt-head is determined bythe relation ofthe operative face of die c to the stop limitin the stroke of the hammer. Usually l cut screw-threads on the shank ot' the die c, and screw it into the reciprocating piece p, holdin g it immovable by use of a check-nut. lhe head of the bolt-carrier or holder g is located in a cylindrical recess of greater diameter, so that there is an annular space around the holderhead. In said head is a wing, b', which in its rotations serves to wipe all of the scales falling from the heated iron lthrough holes made through the casting in the bottom of said annular space. The operative parts of the machine subject to the heat ot' the iron are kept cool in action by the iiow upon them of a small stream of water. The iron being cut ott' to the proper length and the carrier g being suited to its diameter and the pin la to the length of the bolt under the head, the iron is heated nearly or quite to a welding heat and placed in the holder; then, on reciprocation, the die c strikes the head of the hot iron and upsets it or drives it down and the dies 1L a approach and give form to the metal so displaced, the holder g then makes one-sixth of a rotation; the die c descends and more metal is upset, which the dies n n shape, the dies n n receding from the center as the operator draws out the wedges r r; and the operation thus proceeds until the head is fully formed upon the shank of the bolt.

To change the shape of the heads formed by the machine, it will be necessary to change the ratchets h t' and the slide fw so as to have more or less teeth on the former and a different inclined groove in the latter. Ordinarily, however, there need be no departure from devices adapted to produce hexagonal heads.

The operation of forging bolt-heads by the means described, though gradual, is very quickly performed, leaving the ber of the metal in the best condition, and producing a iine sound head without iiaws, fully equal to, ifvnot exceeding, the degree ot' excellence attained by hand-forging.

I claiml. The recessed bed, provided with escape outlets, the winged carrier rotating therein, and mechanism for rotating the same, combined and arranged to operate substantially as described.

2. Also, the combination, with the carrier g, ot' the oppositely arranged equal toothed ratchets lo i, the bar w, the pawl y, and the detaining-pin af, as and for the purpose specilied.

Also, the combination with the slides m a, levers o 0, and reciprocating wedge p and spring o, of the inclines r, arranged to be si multaneously and equally moved by the operator, as set forth.

JEREMIAH GREENWOOD. lNitnesses:

CHARLES H. Foss, OYnUs HAMBLET. 

